Frequently Asked Questions

What are the applicable OSHA regulations concerning in-service testing of rubber insulating products?
29CFR1910.137(b) covers in-service care and use of electrical protective equipment, specifically  insulating blankets, covers, line hose, gloves, and sleeves made of rubber, and specifically references the relevant ASTM specifications.


What ASTM specifications apply to the in-service care of rubber insulating products?
Standard Specification for In-Service Care of:
• ASTM F 478-xx     (Insulating Line Hose & Covers)
• ASTM F 479-xx     (Insulating Blankets)
• ASTM F 496-xx     (Insulating Gloves & Sleeves)
where xx refers to the year that the standard specification was most recently approved.


What are the testing intervals for electrical protective rubber insulating products?
The interval between date of issue and tests should be based on work practices and test experience.  For gloves the interval shall not exceed 6 months except for industries, such as telecommunications, that utilize insulating gloves as precautionary protection, in which case the maximum interval may be increased to 9 months.  For sleeves and blankets, the interval shall not exceed 12 months.  For line hose and covers, no maximum interval is specified; electrical testing shall be performed if the periodic cleaning and visual inspection identifies conditions that might adversely affect performance and safety.


What about retesting unused rubber insulating products?
All electrical protective rubber insulating products are tested by the manufacturer prior to first shipment.  End users (or end users’ designee) may perform acceptance testing within the first 2 months after receipt.  Rubber insulating products shall not be placed into service unless they have been tested electrically within the previous 12 months.


What is involved in the inspection and testing process?
According to ASTM specifications, at a minimum the inspection and testing of rubber insulating products includes check-in, removing previous testing marking, washing using cleaning agents that will not degrade the insulating properties, visual inspection of all surfaces (inside and out), electrical test, final inspection, recordkeeping, marking, and packing in appropriate containers for storage or shipment.  “Appropriate containers” means boxes, or similar sturdy packaging materials to prevent folding, creasing, or similar loose storage that can cause stress on the rubber.


Can rubber insulating products be repaired?
The Voltgard Test Lab does not believe that repairing or trimming defective rubber insulating products is good practice and such repairs will not be performed.


Who is qualified to perform in-service inspection and testing of rubber insulating products?
Many electric power utilities operate their own dielectric test facility to perform acceptance and in-service testing of rubber insulating products.  There are also independent testing facilities, such as the Voltgard Test Lab, that can perform the acceptance and in-service testing on behalf of end users. 


What is “NAIL” and what does it mean to be a NAIL-Accredited Test Lab?
NAIL (or formally NAILforPET) formed in 1978, stands for National Association of Independent Laboratories for Protective Equipment Testing.  It incorporates the only Laboratory Accreditation for electrical equipment test labs Program in the United States and Canada that meets ASTM criteria. The criteria include laboratory facility, equipment, training and knowledge of staff, quality control work procedures, and more. Today the NAIL program is recognized throughout the US and Canada as an important asset to the credentials of a testing facility.


The Voltgard Test Lab is fully NAIL accredited for testing a wide range of rubber insulating products and related tools.


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